Direction

1. Heat the oven to 350°F. Spray and line 2 half-sheet pans (18x13-inch) with cooking parchment paper. In the bowl of a stand mixer or using a hand-held mixer, mix together the cake mix, granulated sugar, water, eggs, 1 tablespoon vanilla, and oil until combined, about 1 minute. Add in the flour, 1/2 teaspoon salt, and sour cream; mix on medium speed until incorporated and without lumps, 2 to 3 minutes.
2. Divide the batter evenly between pans and smooth; the cakes will be thin. Bake for 15 to 18 minutes or until completely baked through. Remove from the oven, and allow to cool at room temperature for 30 minutes before refrigerating for 30 to 60 minutes.
3. In the bowl of a stand mixer or using a hand-held mixer, beat the marshmallow creme and butter on medium high speed until smooth, about 1 minute. Add in the powdered sugar, 1 teaspoon vanilla, 1/2 teaspoon salt, and heavy cream or milk. Mix on medium speed until smooth, adding additional heavy cream as needed until it reaches desired consistency. You want it spreadable but not too thin.
4. Once the cake has cooled, use a 2-inch hexagon-shaped cookie cutter to cut out 40 hexagons. The cake is soft, so in between cuts, I dip the cookie cutter in flour to avoid the cake sticking. Spread the filling on top of half of the shapes, and top with another. Place on a rimmed sheet pan lined with wax paper or cooking parchment paper. Freeze for 1 hour or up to 24 hours. The longer these are frozen, the easier they are to work with!
5. In a large heatproof bowl, melt the candy coating for 30 seconds at a time, stirring in between, until totally melted. Stir in the shortening until smooth. Allow to cool for 3 to 5 minutes before dipping in the cakes.
6. Dip the frozen cakes completely into the melted candy coating, and place onto a cooling rack covered in wax paper or cooking parchment paper. Immediately top with the sprinkles, and allow to set for 15 minutes before serving.